Back in 2004, voters approved the quarter-cent Advanced Transportation District sales tax with proceeds split between VIA, the city of San Antonio, Bexar County and the Texas Department of Transportation.

The passage came with a promise from campaign leaders: none of the funds would go toward light rail, which had overwhelmingly been voted down in 2000.

The centers will serve as hubs for VIA's planned 5.9-mile streetcar route. And as such, Campbell believes ATD funds can't be used there.

We don't believe a streetcar system is the same as light rail.

But even if you set the rail distinction aside, it's hard to accept Campbell's argument.

Why? Because the transit centers will include streetcars and buses. This includes Primo, VIA's bus rapid transit system.

This leads to a crucial distinction: The funding sources for streetcar and bus improvements at the transit centers are separate.

“None of the ATD dollars would be used toward streetcar improvements,” said Jeff Arndt, VIA's president and CEO.

Streetcar improvements will be paid from the streetcar budget, he said. Bus improvements from ATD dollars.

In her letter to Abbott, Campbell says ATD revenue should be used for “its intended purpose — to improve San Antonio's roads.”

That also sounds good, but it's not accurate.

As the Express-News' Vianna Davila has reported, the ATD ballot language states the funds will be evenly split between roads and public transit.

In that light, funding improvements at the multimodal centers would fit ATD's “intended purpose.”

This question of ATD funding has come up in the past. In 2012, Jeff Wentworth, Campbell's predecessor, unsuccessfully challenged the use of such funds for the streetcar project. He also appealed to Abbott to intervene, but the attorney general declined to do so. We hope Abbott shows similar wisdom in this case.

In many ways, VIA has brought this upon itself. The transit agency failed to promptly respond to Campbell's letter, essentially giving it credence. Now, we have a lawsuit.

Opponents have concerns about streetcars: the cost, rail's lack of flexibility, the potential cuts to the bus system.